Hydraulic elevator jack units



Nov. 27, 1962 R. F. LOUGHRIDGE HYDRAULIC ELEVATOR JACK UNITS Filed March6, 1961 IHI W A .W l

United States Patent Oflfice 3,655,738 ?atented Nov. 27,, 1962 3,665,738HYDRAULIC ELEVATOR JACK UNITS Robert F. Loughridge, Fort Worth, Tex.,assignor to Eseo Elevators, Inca, Fort Worth, Tex. Filed Mar. 6, 1961,ger. No. 93,451 Claims. ((11. 121-46) My invention relates to hydraulicelevators, and more particularly to apparatus and arrangements involvinghydraulic elevator jack units.

In hydraulic elevator installations, it is necessary that the elevatorlift plunger extend below ground level. The plunger operates within acylinder or housing which contains the hydraulic fluid which is pumpedunder pressure to power the elevator. Thus, the major portion of thejack unit length is beneath ground level with the cylinder or housingexterior exposed to the earth. In spite of best efforts, such aswrapping, coating, and the like, the jack unit cylinder or housing issubject to corrosion and erosion due to both chemical and electrolysisaction. When such corrosion or erosion or both progress sufliciently,the cylinder or housing will become ruptured, allowing loss of hydraulicfluid and consequent elevator malfunction. In some cases, the rupturemay be sudden and extensive, causing the elevator to drop, with possiblydisastrous results.

The general object of the present invention is to provide improvedelevator jack units. A more specific object is to provide improved jackunit housing arrangements which will give advance warning of housingruptures, and which will prevent the possibility of accident due tosudden and extensive housing rupture. A further object is to provideimproved jack unit arrangements which will allow the elevator to beplaced back into normal operation immediately, following the occurrenceof a housing rupture.

The present invention contemplates that the portion of the jack unitcylinder or housing that is beneath ground level and exposed tocorrosion and erosion action shall have a double wall, with a hydraulicfluid flow passage of selected size communicating between the inner wallinterior and the space between the two housing walls. Thus, the housinginner wall will not be exposed, and cannot corrode or erode. Hydraulicfluid will fill the space between the inner and outer Walls so that whenthere is an outer wall rupture, the hydraul c fluid loss will be at acontrolled rate determined by the selected size of the fluid flowpassage above mentioned. This controlled fluid flow rate may be such asto cause a noticeable downward drop of the elevator so that theexistence of a housing exterior wall rupture will be apparent, but thisdownward drift cannot exceed the rate determined by the fluid flowpassage, and thus the elevator would never fall even if a sudden andextensive rupture occurred. In a preferred form of the invention, thecontrolled fluid flow passage would be located above ground and wouldextend from the exterior of the inner wall to the exterior of the outerwall and thus be accessible so that, when a rupture occurs, the elevatorcan be immediately placed back in normal operation by merely pluggingthe passage. Also, if desired, a valve could be interposed in thepassage so that the fluid flow rate could be adjusted to any ratedesired, and also could be shut off entirely upon occurrence of arupture. Such a valve, though convenient, would be subject to the hazardthat it might be inadvertently left in the closed position so that theoccurrence of a rupture would not be apparent.

The 'way in which the present invention achieves its aims will befurther understood from the following description of a preferredembodiment (given for purposes of illustration and without unnecessarilylimiting the scope of the invention), and taken in accordance with theappended drawings, forming a part of this application, in which:

FIGURE 1 is a schematic view, partially in section, showing a jack unitin accordance with the present invention, in a typical installation;

FIGURE 2 is a schematic longitudinal section view of a jack unitembodying the principals of my invention; and

FIGURE 3 is a schematic view, partly in section, illustratinginstallation of a jack unit in accordance with the invention to replacea jack unit that has failed due to erosion and corrosion.

In FIGURE 1 there is shown a jack unit 11 extending down into a well inthe ground 13. The jack unit includes an inner housing or cylinder 15which is nested within an outer housing or cylinder 17. The outerhousing has a plurality of load support pads 19 disposed around itsouter periphery and integrally fixed to the outer housing a shortdistance below the upper end thereof. These pads rest on the floor 21 ofthe elevator pit 23 and serve to support the elevator and its load uponthe pit floor. The elevator car 25 travels within the guide way 27 andis fixed by suitable bolts 29 to a flange 31 which is integral with theupper end of the jack unit plunger 33. The jack unit outer housing 17has an integral ring flange 35 at its upper end. The jack unit innerhousing is provided an integral ring flange 37 a short distance belowits upper end, and this ring flange 37 rests upon the ring flange 35, sothat the inner housing 15 is actually supported by the outer housing 17.The flanges 35 and 37 are clamped together by suitable bolts 39. Agasket (not shown) may be provided between the flanges 35 and 37 to makea hydraulic fluid-tight seal. The jack unit inner housing has anintegral ring flange 41 at its upper end which is mated in fluid-tightrelation with a ring flange 43 which in turn is a part of a plungerguide and packing assembly 45. The plunger guide and packing assembly 45is of a conventional type and is clamped to the jack unit inner housing15 by means of bolts 47.

The inner housing 15 together with the plunger guide and packingassembly 45 provides a fluid-tight container. Hydraulic fluid is pumpedinto the container via inlet 49 to exert pressure on the plunger lowerend 51 to raise the elevator and its load. When the elevator isdescending, fluid is allowed to escape at a controlled rate via inlet 49and suitable valves and conduits to a hydraulic fluid reservoir (notshown).

The diameter of the jack unit inner housing exterior is less than thatof the jack unit outer housing interior. Also, the extremity of theinner housing bottom exterior is preferably above the bottom of theouter housing interior. Thus, there is found an annular space 51 and acylindrical space 53 between the exterior of the inner housing 15 belowthe ring flange 37 and the interior of the outer housing 17. This space51 and 53 is hydraulic fluid-tight, and is interposed between the innerand outer housings 15 and 17 over the entire region of exposure of theouter housing 17 to corrosion and erosion due to chemical andelectrolysis action. The inner housing 15 has a threaded opening 55located immediately above ring flange 37; and the outer housing 17 has asimilar threaded opening 57 located immediately below ring flange 35. Aconduit 59, made up of nipples 61, elbows 63, and a union 65communicates from the inner housing interior via opening 55 to the space51 and 53 be tween the inner and outer housing, via opening 57.

It should be apparent from the foregoing that the elevator jack unitsmade in accordance with the principals of my invention are effective togive notice of housing ruptures, to prevent elevator drop due to suddenand extensive housing ruptures, and to allow immediate return ofelevator to normal service following occurrence of a rupture.

The jack units of my invention are applicable as replacements inexisting installations as 'well as for new ones. The application to anexisting installation is illustrated by FIGURE 3, wherein there is shownthe housing 59 of an old jack unit housing which has eroded and rupturedat 61. The old housing has been cut off just above the floor of the pit21 and a new jack unit has been inserted in the old housing. The outerhousing 17 of the new jack unit has been welded at 63 to the upper endof the old housing 59 to prevent water from rising up into the pit 21.

While I have shown my invention in only one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications without departing from the spiritthereof.

I claim:

1. A jack unit for a hydraulic elevator comprising an outer cylindricalhousing adapted for insertion in an earth well with an upper portionprotruding above ground and terminating in an annular flange, an innercylindrical housing having an integral exterior ring flange beneath itsupper end and mating with said annular flange to support said innerhousing on said outer housing in nested spaced relation, means joiningsaid flanges in hydraulic fluid-tight relation, and a hydraulic fluidconduit communicating from said inner housing interior above saidflanges to said outer housing interior below said flanges and exteriorlyof both said housings.

2. A jack unit for a hydraulic elevator comprising an outer housingadapted for contact with earth below ground, an inner housing supportedon said outer housing in nested relation thereto, said inner housingadapted for receiving an elevator load carrying plunger for reciprocablemotion and in hydraulic fluid-tight relation, with said housingsdefining a hydraulic fluid-tight housing therebetween, means providingingress and egress of hydraulic fluid to said inner housing, and meansallowing controlled leakage of hydraulic fluid from said inner housingto said outer housing.

3. A jack unit for a hydraulic elevator comprising an outer housingadapted for contact with earth below ground, an inner housing supportedon said outer housing in nested relation thereto, said inner housingadapted for receiving an elevator load carrying plunger for reciprocablemotion and in hydraulic fluid-tight relation, with said housingsdefining a hydraulic fluid-tight housing therebetween, means providingingress and egress of hydraulic fluid to said inner housing, meansaccessible and aboveground for allowing controlled leakage of hydraulicfluid from said inner housing to said outer housing.

4. A jack unit for a hydraulic elevator comprising an outer housing forinsertion into an earth well with an upper portion protrudingaboveground, an inner housing nested within said outer housing andspaced therefrom so as to define a hydraulic fluid-tight cavitytherebetween, with said inner housing protruding above the upper portionof said outer housing, and a fluid conduit communicating between saidinner housing and said outer housing exteriorly of both said housings.

5. A jack unit for a hydraulic elevator, said jack unit comprising aplunger, an inner housing adapted for receiving said plunger forreciprocable motion and in hydraulic fluid-tight relation, an outerhousing adapted for receiving said inner housing in nesting spacedrelation, a hydraulic fluid supply opening in said inner housing, and ahydraulic fluid passage communicating between said References Cited inthe file of this patent UNITED STATES PATENTS 654,876 Dean July 31, 19001,720,434 Pedersen July 9, 1929 FOREIGN PATENTS 38,196 Germany June 11,1886

